On Wed, 31 Jan 2024, Maciej Wieczor-Retman wrote:
On 2024-01-26 at 10:58:04 -0800, Reinette Chatre wrote:
On 1/25/2024 4:14 AM, Ilpo Järvinen wrote:
On Thu, 25 Jan 2024, Maciej Wieczor-Retman wrote:
- fp = fopen(file_path, "r");
- if (!fp) {
snprintf(reason, sizeof(reason), "Error in opening %s file\n", filename);ksft_perror(reason);Was this the conclusion of the kstf_perror() discussion with Reinette? I expected a bit different outcome when I stopped following it...
In any case, it would be nice though if ksft_perror() (or some kselftest.h function yet to be added with a different name) would accept full printf interface and just add the errno string into the end of the string so one would not need to build constructs like this at all.
It will require a bit of macro trickery into kselftest.h. I don't know how it should handle the case where somebody just passes a char pointer to it, not a string literal, but I guess it would just throw an error while compiling if somebody tries to do that as the macro string literal concatenation could not build useful/compilable token.
It would make these prints informative enough to become actually useful without needed to resort to preparing the string in advance which seems to be required almost every single case with the current interface.
I think this can be accomplished with a new: void ksft_vprint_msg(const char *msg, va_list args)
... but ksft_perror() does conform to perror() and I expect that having one support variable number of arguments while the other does to cause confusion.
To support variable number of arguments with errno I'd propose just to use ksft_print_msg() with strerror(errno), errno as the arguments (or even %m that that errno handling within ksft_print_msg() aims to support). This does indeed seem to be the custom in other tests.
Does something like this look okay?
fp = fopen(file_path, "r"); if (!fp) { ksft_print_msg("Error in opening %s\n: %m\n", file_path); return -1; }
The '%m' seems to work fine but doesn't print errno's number code. Do you want me to add errno after '%m' so it is the same as ksft_perror()? I looked through some other tests where '%m' is used, and only few ones add errno with '%d'.
I think %m is enough.